What do you think is most foundational of God? What is God most truly? Most ultimately? Is he most ultimately the Creator? The one who brings everything into existence? Is he most ultimately the Ruler? The one who keeps all things in order and makes sure his reign is submitted to in all things? Is he most ultimately the Judge? The one who makes sure justice is always served, crimes are always punished, and righteousness is always upheld? In your thinking, what is God most foundational? Most ultimately?
Though there are many things that could be argued for, I think Michael Reeves nails it on the head: God is most ultimately Father. For before Creation, he was Father. Before there was anything to rule over, He was Father. Before there was anything to judge, he was Father. He has always been Father living in perfect love with His Son. Reeves expands on this helpfully:
The most foundational thing in God is not some abstract quality, but the fact that he is Father. Since God is, before all things, a Father, and not primarily a Creator or Ruler, all his ways are beautifully fatherly. It is not that this God “does” being Father as a day job, only to kick back in the evenings as plain old “God.” It is not that he has a nice blob of fatherly icing on top. He is Father. All the way down. Thus all that he does he does as Father. That is who he is. He creates as a Father and he rules as a Father; and that means the way he rules over creation is most unlike the way any other God would rule over creation…
Only when we see that God rules his creation as a kind and loving Father that we will be moved to delight in his providence. We might acknowledge that the rule of some heavenly policeman was just, but we could never take delight in his regime as we can delight in the tender care of a father. (Taken from Delighting in the Trinity, p. 24).
Yes, God is the Creator, Ruler, and Judge of all, but before he became those things, he was Father. He is the life giving, outgoing Father who seeks to bring life into all things. He is the sender of his Son to make sinners his sons and daughters; to become their Father too.